another little legacy code removal

client/src/mvc/library/library-dataset-view.js

@@ -293,15 +293,6 @@ var LibraryDatasetView = Backbone.View.extend({
         );
     },
 
-    _serializeRoles: function (role_list) {
-        var selected_roles = [];
-        for (var i = 0; i < role_list.length; i++) {
-            // Replace the : and , in role's name since these are select2 separators for initialData
-            selected_roles.push(`${role_list[i][1]}:${role_list[i][0].replace(":", " ").replace(",", " &")}`);
-        }
-        return selected_roles;
-    },
-
     detectDatatype: function (options) {
         const ld = this.model;
         ld.set("file_ext", "auto");